ref: Use Python 3.6 for linting (no sudo!)

.travis.yml

@@ -13,7 +13,7 @@ matrix:
       sudo: true
 
     - name: Linting
-      python: "3.7"
+      python: "3.6"
       install:
         - pip install tox
       script: tox -e linters

tox.ini

@@ -80,7 +80,7 @@ commands:
 
 
 [testenv:flake8]
-basepython = python3.7
+basepython = python3.6
 skip_install = true
 deps =
     flake8
@@ -90,7 +90,7 @@ commands =
     flake8 raven/ setup.py
 
 [testenv:pylint]
-basepython = python3.7
+basepython = python3.6
 skip_install = true
 deps =
     pyflakes
@@ -100,15 +100,15 @@ commands =
 
 
 [testenv:bandit]
-basepython = python3.7
+basepython = python3.6
 skip_install = true
 deps =
     bandit
 commands =
     bandit -r raven/ -c .bandit.yml
 
 [testenv:linters]
-basepython = python3.7
+basepython = python3.6
 skip_install = true
 deps =
     {[testenv:flake8]deps}
@@ -122,15 +122,15 @@ commands =
     {[testenv:bandit]commands}
 
 [testenv:readme]
-basepython = python3.7
+basepython = python3.6
 deps =
     readme_renderer
 commands =
     python setup.py check -r -s
 
 # Release tooling
 [testenv:build]
-basepython = python3.7
+basepython = python3.6
 skip_install = true
 deps =
     wheel
@@ -139,23 +139,23 @@ commands =
     python setup.py -q sdist bdist_wheel
 
 [testenv:release]
-basepython = python3.7
+basepython = python3.6
 skip_install = true
 deps =
     bumpversion
 commands =
     bumpversion --tag --commit {posargs} release
 
 [testenv:minor]
-basepython = python3.7
+basepython = python3.6
 skip_install = true
 deps =
     bumpversion
 commands =
     bumpversion --commit {posargs} minor
 
 [testenv:dev]
-basepython = python3.7
+basepython = python3.6
 skip_install = true
 deps =
     bumpversion